Vehicle traction control system and method

ABSTRACT

A method and system determine, during movement of a vehicle system along a route, a tractive load demanded by the vehicle system to propel the vehicle system along the route. The vehicle system includes a propulsion-generating vehicle having plural individually controllable traction motors. A first selected set of the traction motors for deactivation is identified during the movement of the vehicle system along the route based at least in part on the tractive load demanded by the vehicle system. The traction motors in the first selected set are deactivated while at least one of the traction motors in a first remaining set of the traction motors continues to generate tractive effort to propel the vehicle system. The traction motors that are selected for deactivation may all be on the same vehicle in the vehicle system, or may be on different vehicles of the same vehicle system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/496,655, filed on 25 Sep. 2014, which is a continuation-in-part ofU.S. patent application Ser. No. 13/487,057, filed on 1 Jun. 2012 (nowU.S. Pat. No. 9,545,854), which claims priority to U.S. ProvisionalApplication No. 61/496,556, filed on 13 Jun. 2011. The entiredisclosures of these applications are incorporated herein by reference.

FIELD

Embodiments of the subject matter disclosed herein relate to controllingpropulsion systems of vehicles and/or vehicle systems.

BACKGROUND

Some known vehicles include multiple motors that generate tractive forceto move the vehicles along a route. For example, locomotives may includemultiple traction motors that operate to rotate axles and/or wheels ofthe locomotives. During trips of such vehicles, the amount of tractiveforce needed to propel the vehicles changes. The load of the vehiclescan change over time for a variety of factors, such as wind conditions,adhesion between the wheels and the route, changing amounts of cargobeing carried by the vehicles, or the like.

Because of the changing load of the vehicles, the amount of tractiveforce needed to move the vehicle can change over time. But, some knownvehicles keep all traction motors actively generating tractive force topropel the vehicles, even if some of the traction motors are generatinga relatively small amount of tractive force. Some other known vehicleconsists (e.g., trains) having two or more locomotives may turn off alltraction motors in one of the locomotives when less than all tractionmotors are needed for propelling the consist. These consists rely onsimulations of travel of the consists by an off-board computing system.The simulations determine locations where a locomotive can be turned offprior to the consist embarking on a trip. During the trip, the consistmay refer to the previously simulated travels and turn off a locomotiveat one or more locations based on the simulations.

But, these simulations rely on calculated amounts of tractive forcesneeded to move the consist. Because the simulations are performed priorto embarking on a trip, these consists are unable to adapt to changingconditions during movement. For example, the consists are not able toturn any traction motors on or off based on a real time change in theneeded tractive forces that was not present in the simulations.

BRIEF DESCRIPTION

In one embodiment, a method (e.g., for operating a vehicle tractioncontrol system of a vehicle system during movement of the vehiclesystem) includes, during movement of a vehicle system along a route,determining a tractive load demanded by the vehicle system to propel thevehicle system along the route. The vehicle system includes apropulsion-generating vehicle having plural individually controllabletraction motors. The method also can include identifying a firstselected set of the traction motors for deactivation during the movementof the vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and deactivating thetraction motors in the first selected set while at least one of thetraction motors in a first remaining set of the traction motorscontinues to generate tractive effort to propel the vehicle system. Oneor more of the operations of the method (e.g., the determining of atractive load demanded by the vehicle system, identifying the firstselected set of the traction motors, and/or deactivating the tractionmotors) may be performed by one or more processors disposed onboard thevehicle system.

In another embodiment, a system (e.g., a traction control system)includes one or more processors configured to be disposed onboard avehicle system and to determine, during movement of the vehicle systemalong a route, a tractive load demanded by the vehicle system to propelthe vehicle system. The vehicle system includes a propulsion-generatingvehicle having plural individually controllable traction motors. The oneor more processors also are configured to identify a first selected setof the traction motors for deactivation during movement of the vehiclesystem along the route based at least in part on the tractive loaddemanded by the vehicle system and to deactivate the traction motors inthe first selected set while at least one of the traction motors in afirst remaining set of the traction motors continues to generatetractive effort to propel the vehicle system.

In another embodiment, another system (e.g., another traction controlsystem) includes one or more processors configured to monitor tractiveloads demanded to propel a vehicle system along a route as the vehiclesystem moves along the route. The one or more processors are configuredto identify one or more traction motors of a vehicle in the vehiclesystem to turn off based at least in part in a change in the tractiveloads demanded to propel the vehicle system. The one or more processorsare configured to generate control signals to turn off the one or moretraction motors while one or more other traction motors remain on togenerate tractive forces that meet or exceed the tractive loads demandedto propel the vehicle system during movement of the vehicle system alongthe route.

In another embodiment, another method (e.g., for controlling a tractioncontrol system) includes, during movement of a vehicle system along aroute, determining a tractive load demanded by the vehicle system topropel the vehicle system along the route. The vehicle system includes afirst propulsion-generating vehicle having a first plurality ofindividually controllable traction motors and a secondpropulsion-generating vehicle having a second plurality of individuallycontrollable traction motors. The first and second vehicles are linkedto travel together along the route. The method also includes identifyinga first selected set of the first plurality of traction motors fordeactivation during movement of the vehicle system along the route basedat least in part on the tractive load demanded by the vehicle system,deactivating the traction motors in the first selected set while atleast one of the traction motors in a first remaining set of the firstplurality of traction motors continues to generate tractive effort topropel the vehicle system, identifying a second selected set of thesecond plurality of traction motors for deactivation during movement ofthe vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and deactivating thetraction motors in the second selected set while at least one of thetraction motors in a second remaining set of the second plurality oftraction motors continues to generate tractive effort to propel thevehicle system.

In another embodiment, another system (e.g., another traction controlsystem) includes one or more processors configured to be disposedonboard a vehicle system and to determine, during movement of thevehicle system along a route, determine a tractive load demanded by thevehicle system to propel the vehicle system along the route. The vehiclesystem includes a first propulsion-generating vehicle having a firstplurality of individually controllable traction motors and a secondpropulsion-generating vehicle having a second plurality of individuallycontrollable traction motors, the first and second vehicles being linkedto travel together along the route. The one or more processors also areconfigured to identify a first selected set of the first plurality oftraction motors for deactivation during movement of the vehicle systemalong the route based at least in part on the tractive load demanded bythe vehicle system, and to deactivate the traction motors in the firstselected set while at least one of the traction motors in a firstremaining set of the first plurality of traction motors continues togenerate tractive effort to propel the vehicle system. The one or moreprocessors also are configured to identify a second selected set of thesecond plurality of traction motors for deactivation during movement ofthe vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and to deactivate thetraction motors in the second selected set while at least one of thetraction motors in a second remaining set of the second plurality oftraction motors continues to generate tractive effort to propel thevehicle system.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings in which particularembodiments and further benefits of the invention are illustrated asdescribed in more detail in the description below, in which:

FIG. 1 is a flowchart of a method for operating a vehicle tractioncontrol system of a vehicle system during movement of the vehicle systemaccording to one embodiment;

FIG. 2 is a schematic diagram of a vehicle system having a tractioncontrol system according to one embodiment;

FIG. 3 illustrates a circuit diagram of a propulsion system and atraction control system according to one embodiment;

FIG. 4 illustrates efficiency indices of different operating states oftraction motors shown in FIG. 3 of a propulsion-generating vehicle shownin FIG. 2 according to one example; and

FIG. 5 illustrates operating temperatures of traction motors shown inFIG. 3 according to one example of operation of the propulsion systemshown in FIG. 3.

DETAILED DESCRIPTION

One or more embodiments described herein provide systems and methods forindividually controlling which traction motors in a vehicle havingmultiple traction motors are activated or deactivated at different timesduring movement of the vehicle. The different traction motors of thevehicle can be operably coupled with different axles and/or wheel setsof the vehicle such that the activated traction motors work to rotatethe axles and/or wheel sets to propel the vehicle while the deactivatedtraction motors do not work to rotate the axles and/or wheel sets. Thevehicle can be included in a larger vehicle system having one or moreother vehicles connected with each other, such as a vehicle consist.During movement along a route, a tractive load demanded to propel thevehicle system along the route can be determined. This tractive load canbe compared to the capabilities of the traction motors to producetractive effort. If fewer than all of the traction motors in a vehiclecan be activated and still provide at least the tractive load demandedby the vehicle system (or at least the portion of the tractive load thatis attributable to the vehicle), then one or more of the traction motorsmay be deactivated while the remaining traction motors in the vehicleremain activated. The selection of which traction motors in a vehicleare activated or deactivated can change over time based on changes inthe tractive load demanded by the vehicle system to propel the vehiclesystem. In one aspect, the selection of which traction motors areactivated or deactivated is performed based at least in part inoperating temperatures of the traction motors. For example, the tractionmotors having larger operating temperatures than one or more othertraction motors may be selected for deactivation.

The systems and methods described herein operate according to a strategyto channel horsepower produced by traction motors more efficiently thancurrently known systems and methods. In conditions where the vehiclesystem has lesser tractive loads demanded to propel the vehicle system(e.g., light load conditions, such as when a locomotive is lightlyloaded with a light train or an empty train, fast moving speeds duringlower throttle notches, etc.), the traction motors may underloaded, andmay not be operating in an efficient manner. Under such conditions, byturning off one or more traction motors, the load on the other tractionmotors may increase. Instead of underloading the traction motors, it canbe possible to increase the load on the traction motors to or near therated values of the traction motors by deactivating other tractionmotors. The load can be increase to or near the rated values of thetraction motors when the load is increased to be equivalent to or withina designated range (e.g., 1%, 5%, 10%, or the like) of the ratedcapacities of the traction motors. In one aspect, the rated capacity ofa traction motor may be the maximum power rating of the traction motor,or a designated limit of the power output of the traction motor otherthan the maximum power rating (e.g., 60%, 70%, 80%, 90%, or the like, ofthe maximum power rating).

Changing the loading of the traction motors can lead to improvedoperating efficiencies without sacrificing performance and, as a result,energy consumption can be reduced (such as by at least 1%) relative tonot changing the loading of the traction motors. For example, if thesame vehicle system travels over the same routes during the sameconditions between the same locations during a first trip where alltraction motors remain activated during the entire trip and during adifferent, second trip where the traction motors are selectivelyactivated or deactivated during movement in the trip, the vehicle systemmay consume at least 1% less energy during the second trip than duringthe first trip.

FIG. 1 is a flowchart of a method 100 for operating a vehicle tractioncontrol system of a vehicle system during movement of the vehicle systemaccording to one embodiment. FIG. 2 is a schematic diagram of a vehiclesystem 200 having a traction control system 202 according to oneembodiment. The method 100 may be performed by one or more embodimentsof the traction control system 202. For example, one or more processorsof the vehicle system 200 can perform the operations of the method 100.At 102, the vehicle system 200 moves along a route 204 (shown in FIG.2). The vehicle system 200 represents a vehicle consist, such as a railvehicle consist, having propulsion-generating vehicles 206 (e.g.,vehicles 206A-C) and non-propulsion-generating vehicles 208 (e.g.,vehicles 208A-B) mechanically coupled together by couplers 210. Whilethe description herein focuses on the vehicle system 200 being a railvehicle consist (e.g., a train) having locomotives as the vehicles 206and railcars as the vehicles 208, alternatively, one or more embodimentsdescribed herein may be applied to other types of vehicle consistsand/or vehicles, such as other off-highway vehicles (e.g., miningvehicles or other vehicles that are not designed or permitted for travelon public roadways), marine vessels, automobiles, or the like.

The vehicles 206 include propulsion systems 212 comprising severaltraction motors (shown and described below) operably coupled withdifferent axles 214 and/or wheels 216 of the vehicles 206. The tractionmotors may be connected with the axles 214 and/or wheels 216 via one ormore gears, gear sets, or other mechanical devices to transform rotarymotion generated by the traction motors into rotation of the axles 214and/or wheels 216 to propel the vehicles 206 and, consequently, thevehicle system 200. Different traction motors may be operably connectedwith different axles 214 and/or wheels 216 such that traction motorsthat are deactivated (e.g., turned OFF) do not rotate correspondingaxles 214 and/or wheels 216 while traction motors that remain activated(e.g., turned ON) rotate corresponding axles 214 and/or wheels 216.

Returning to the description of the method 100 shown in FIG. 1, at 104,a tractive load demanded by the vehicle system 200 is determined. Thetractive load demanded by the vehicle system 200 can represent theamount of tractive effort or power (e.g., horsepower) that is calculatedas being necessary to propel the vehicle system 200 over an upcomingsegment of the route 204. The tractive load demanded by the vehiclesystem 200 can be calculated based on a variety of factors, such as thesize of the vehicle system 200 (e.g., the weight, mass, length, or thelike, of the vehicle system 200), the curvature of the route 204, thegrade of the route 204, weather conditions (e.g., wind direction, windspeed, precipitation, ambient temperature, or the like), adhesion of thewheels 214 to the route 204, locations of the vehicles 206 in thevehicle system 200, or the like. For example, as the size of the vehiclesystem 200 increases, a radius of curvature of the route 204 decreases,the grade of the route 204 increases, the weather conditions become moreadverse (e.g., headwinds become stronger), adhesion increases, or thelike, then the tractive load demanded may increase. Conversely, as thesize of the vehicle system 200 decreases, a radius of curvature of theroute 204 increases, the grade of the route 204 decreases, the weatherconditions become less adverse, adhesion decreases, or the like, thenthe tractive load demanded may decrease. The tractive load demanded maybe calculated from one or more mathematical or physics-based models ofthe vehicle system 200 and the route 204, and/or may be based onprevious trips of the vehicle system 200 and/or another vehicle system200 along the route 204.

In one aspect, the tractive load demanded by the vehicle system 200 canbe determined independent of the location of the vehicle system 200. Forexample, instead of determining how much tractive effort is needed atvarious locations along the route to propel the vehicle system 200,monitoring locations of the vehicle system 200, and then determining thetractive load demanded by the vehicle system 200 as a function oflocation, the tractive load demanded by the vehicle system 200 may bedetermined based at least in part on the current movement of the vehiclesystem 200. If the vehicle system 200 is traveling slower than adesignated speed (e.g., a speed limit of the route, a speed selected byan onboard operator, a speed dictated by a trip plan or speed profilethat designates speeds as a function of time and/or distance along theroute, or the like), then the tractive load demanded by the vehiclesystem 200 can increase. Conversely, if the vehicle system 200 istraveling faster than the designated speed, then the tractive loaddemanded by the vehicle system 200 can decrease.

At 106, a determination is made as to whether a different number and/orset of the traction motors in one or more of the vehicles 206 of thevehicle system 200 can be activated to provide at least the tractiveload demanded by the vehicle system 200. For example, if all tractionmotors of the vehicles 206 in the vehicle system 200 are activated andgenerating tractive force to propel the vehicle system 200, then adetermination may be made as to whether a lesser number of the tractionmotors can be activated (with one or more traction motors being turnedoff), while still generating at least enough tractive force to providethe tractive load demanded by the vehicle system 200.

If the currently activated traction motors are needed to remainactivated to produce at least the tractive load demanded by the vehiclesystem 200, then it may not be possible to deactivate one or more of thetraction motors while still generating at least the tractive loaddemanded by the vehicle system 200. As a result, flow of the method 100can proceed to 108. At 108, the currently activated traction motorsremain activated to continue generating at least the tractive effortdemanded by the vehicle system 200. The vehicle system 200 can continuemoving along the route using the same activated traction motors, andflow of the method 100 can return to 102.

On the other hand, if one or more traction motors can be deactivatedwhile the remaining traction motors remain on to propel the vehiclesystem 200 by providing at least the tractive load demanded by thevehicle system 200, then flow of the method 100 can proceed to 110. Forexample, a selected set of one or more traction motors may bedeactivated, but the tractive force provided by the remaining tractionmotors (that remain activated) may be increased so that the summedoutput of the remaining, activated traction motors at least meets thedemanded tractive load.

At 110, a selected set of one or more traction motors is identified fordeactivation, and/or a remaining set of one or more traction motors isidentified to be activated (e.g., if the motors are currentlydeactivated) and/or is identified to remain activated. Theidentification of which motors to activate and which to deactivate canoccur during movement of the vehicle system 200 along the route.

The traction motors can be identified for deactivation and/or foractivation based on at least in part on actual output capabilities ofthe traction motors, rated capacities of the traction motors, operatingtemperatures of the traction motors, or the like. The actual outputcapabilities represent how much tractive effort or force that thetraction motors are actually able to generate. Due to age, damage, orthe like, the amount of tractive effort or force that a traction motoris able to generate can decrease over time. The decreasing abilities ofthe traction motors can be used to determine which traction motors toselect for activation or deactivation. For example, newer and/or lessdamaged traction motors may be selected for activation to provide largerdemanded traction loads of the vehicle system relative to older and/ormore damaged traction motors.

The rated capacities of the traction motors can represent designatedlimits on the amount of tractive effort or force provided by thetraction motors. The rated capacities can represent power ratings of themotors, such as the amount of watts, horsepower, or the like, that themotors are designed and/or designated to provide. The rated capacitiesmay not represent the maximum power outputs that the motors are capableof generating, but may instead be less than the maximum power outputs.Alternatively, the rated capacities can represent the largest poweroutputs that the motors are able to generate. The selection of whichmotors to activate and/or which motors to deactivate may be made basedon the rated capacities by selecting those motors having combined ratedcapacities that meet or exceed the tractive load demanded by the vehiclesystem 200.

The operating temperatures of the traction motors represent thetemperatures at which the traction motors are operating. The operatingtemperatures may not represent the ambient temperature or thetemperature around the motors, but instead may represent how hot themotors are. The traction motors may be selected for activation and/ordeactivation based at least in part on the operating temperatures of thetraction motors to avoid overheating and/or damaging the motors. Forexample, if the operating temperature of a motor is at or above adesignated upper temperature limit, then that motor may be selected fordeactivation and/or may be excluded from being selected for activation.As another example, if the operating temperature of the motor is at orbelow a designated lower temperature limit, then that motor may beselected for activation and/or excluded from being selected fordeactivation. The operating temperatures of the traction motors may bemonitored over time to ensure that the traction motors do not overheat.If the operating temperatures of some traction motors become too large,then those traction motors may be selected for deactivation anddeactivated while the vehicle system 200 is moving to allow the tractionmotors to cool down. One or more of these traction motors may later beselected for activation responsive to the operating temperatures of theone or more traction motors decreasing to or below a limit, such as thelower temperature limit.

In one aspect, the traction motors that are selected for deactivationmay all be on a single vehicle of the vehicle system. For example, asubset of the traction motors on a first vehicle in the vehicle systemmay be selected for deactivation, while the remaining traction motor ormotors in the first vehicle may not be selected for deactivation and thetraction motors on other vehicles in the vehicle system are not selectedfor deactivation. In another aspect, the traction motors that areselected for deactivation may span across multiple different vehicles inthe same vehicle system. For example, the set of the traction motorsthat is selected for deactivation may include at least one tractionmotor of a first vehicle and at least one traction motor of a secondvehicle in the same vehicle system, while one or more other tractionmotors of the first vehicle and one or more other traction motors of thesecond vehicle are not selected for deactivation.

At 112, the traction motors that were selected for deactivation aredeactivated and/or the traction motors that were selected for activationare activated. For example, if a first and third traction motor of onevehicle 206A are selected for deactivation, a second and third tractionmotor of another vehicle 206B are selected for deactivation, and a fifthtraction motor of another vehicle 206C are selected for deactivation,then those traction motors may be turned off while the vehicle system200 moves along the route. Optionally, one or more deactivated tractionmotors may be turned on while the vehicle system 200 moves along theroute.

Flow of the method 100 can return to 102 so that the vehicle system 200continues to move along the route, and the determination of the tractiveload demanded by the vehicle system 200, the determination of whether adifferent number and/or set of traction motors may be used to provide atleast the tractive load demanded, the identification of which tractionmotors to activate and/or deactivate, and the activation and/ordeactivation of the traction motors can be repeated one or more timesduring movement of the vehicle system 200. For example, at one or moretimes when the tractive load demanded by the vehicle system 200 changes,the identification and/or deactivation of one or more traction motorscan be repeated so that the traction motors in the vehicle system 200are not generating significantly more or less tractive effort than whatis needed to meet the tractive load demanded by the vehicle system 200.

In one aspect, operating states of the traction motors that are selectedfor activation or that are not deactivated can be modified by increasingthe tractive effort provided by these traction motors. For example, in avehicle 206, if two of six traction motors are deactivated and the otherfour traction motors are activated, then the tractive effort generatedby the activated traction motors can be increased. The tractive effortcan be increased in order to meet the tractive load demanded by thevehicle system 200. In one embodiment, the output of the traction motorscan be increased to or above one or more limits, such as by increasingthe power output of the traction motors to or above the rated capacitiesof the traction motors. For example, if the activated traction motors donot have sufficiently large rated capacities to meet or exceed thetractive load demanded by the vehicle system 200, then one or more ofthe traction motors may be operated above the rated capacities of theone or more traction motors such that the total output of the activatedtraction motors is at least as large as the tractive load demanded bythe vehicle system 200.

FIG. 3 illustrates a circuit diagram of a propulsion system 300 and atraction control system 302 according to one embodiment. The propulsionsystem 300 can represent one or more of the propulsion systems 212 shownin FIG. 2 and the control system 302 can represent the control system202 shown in FIG. 2. The propulsion system 300 includes one or moreengines 304 that are operably connected with an alternator or generator306 (“Alternator” in FIG. 3) by one or more shafts 308. The engine 304rotates the shaft 308 to cause the alternator or generator 306 togenerate electric current. This electric current is supplied to arectifier 310, which then supplies the current to several inverters 312(“Inverter 1,” “Inverter 2,” “Inverter 3,” “Inverter 4,” “Inverter 5,”and “Inverter 6” in FIG. 3). The inverters 312 are connected withdifferent traction motors 314 (“TM1,” TM2,” “TM3,” “TM4,” “TM5,” and“TM6” in FIG. 3) in the illustrated embodiment. The inverters 312 alsoare operably connected with the control system 302. The control system302 can control which traction motors 314 are activated or deactivated,and/or the operating state of the traction motors 314, via controlsignals that are communicated to the inverters 312. For example, thecontrol system 302 can communicate different control signals todifferent inverters 312 via one or more wired and/or wirelessconnections to individually control which ones of the inverters 312activate the corresponding traction motors 314, which inverters 312deactivate corresponding traction motors 314, the current supplied fromthe inverters 312 to the corresponding traction motors 314 (e.g., tocontrol the power outputs from the traction motors 314), or the like.

Several traction motor blowers 316 (“TMB1” and “TMB2” in FIG. 3)represent fans that move air toward the traction motors 314 in order tocool the traction motors 314. One traction motor blower 316 may coolseveral traction motors 314 in one embodiment. The speeds at which thetraction motor blowers 316 operate may be controlled via control signalscommunicated from the control system 302 to the traction motor blowers316. Several temperature sensors 318 sense or measure the operatingtemperatures of the traction motors 314 and generate data representativeof the operating temperatures of the traction motors 314. This data canbe communicated to the control system 302. As described above, thecontrol system 302 can at least partially base the selection of whichtraction motors 314 to turn ON or OFF based on the operatingtemperatures of the traction motors 314.

As described above, the control system 302 can deactivate one or moretraction motors 314 and optionally increase the operating state of oneor more other traction motors 314 so that the combined power output ofthe activated traction motors 314 meets or exceeds the tractive loaddemanded by the vehicle system 200. Doing so can increase the efficiencyof the propulsion system 300 relative to propelling the vehicle system200 with a larger number of activated traction motors 314.

FIG. 4 illustrates efficiency indices 400, 402, 404 of differentoperating states of traction motors 314 (shown in FIG. 3) of apropulsion-generating vehicle 206 (shown in FIG. 2) according to oneexample. The efficiency indices 400, 402, 404 are shown alongside ahorizontal axis 406 representative of moving speeds of the vehicle 206and alongside a vertical axis 408 representative of efficiencies of thevehicle 206. The efficiency indices 400, 402, 404 represent howefficiently the propulsion system 300 of the vehicle 206 operate withdifferent numbers of traction motors 314 being activated. The efficiencyindex 400 represents the efficiency of the propulsion system 300operating with all six traction motors 314 being activated at differentspeeds of the vehicle 206. The efficiency index 402 represents theefficiency of the propulsion system 300 operating with five tractionmotors 314 being activated and one traction motor 314 being deactivatedat different speeds of the vehicle 206. The efficiency index 404represents the efficiency of the propulsion system 300 operating withfour traction motors 314 being activated and two traction motors 314being deactivated at different speeds of the vehicle 206. The efficiencyindices 400, 402, 404 can be measured or calculated based on losses inelectric current that is generated by the alternator or generator 306(shown in FIG. 3), but that is not converted into tractive effort by oneor more traction motors 314. For example, larger efficiency indices 400,402, 404 at a particular speed indicate that less electric current islost and not being converted into tractive effort relative to smallerefficiency indices 400, 402, 404 at the same speed.

As shown in FIG. 4, for a particular route and at a speed of the vehicle206, there are three options for which traction motors 314 are turned onor off (e.g., no traction motors 314 being deactivated, as representedby the indices 400; one traction motor 314 being deactivated, asrepresented by the indices 402; or two traction motors 314 beingdeactivated, as represented by the indices 404). The option thatprovides the largest or a larger efficiency may be selected. Forexample, at a first speed 410, one traction motor 314 may be turned offwhile the remaining five traction motors 314 remain on. But, at afaster, second speed 412, two traction motors 314 may be turned offwhile four traction motors 314 remain on to provide for increasedefficiency of the vehicle 206 (relative to another combination oftraction motors 314 being turned off).

The efficiency at which a vehicle 206 and/or the vehicle system 200operates also may be increased by reducing the amount of electriccurrent that is consumed by the traction motor blowers 316. For example,the electric power consumed by a traction motor blower 316 when thetraction motor blower 316 is operating at full speed is approximatelyeight times the electric power consumed by the same traction motorblower 316 operating at half speed. In order to reduce the amount ofelectric current consumed (and thereby increase the efficiency in whichthe vehicle 206 and/or vehicle system 200 operates), the control system302 optionally can reduce the operating speeds of the traction motorblowers 316. In one embodiment, the control system 302 turns off thetraction motor blowers 316 that work to cool the traction motors 314that are turned off, and/or reduces the operating speed (e.g., the speedat which the traction motor blower 316 operates to move air to cool thetraction motor 314) of the traction motor blowers 316 that remain on tocool the traction motors 314 that remain on. Doing so can furtherincrease the efficiency at which the vehicle 206 and/or vehicle system200 operates. Increasing the efficiency of the vehicle 206 and/orvehicle system 200 can reduce the amount of fuel consumed by the vehicle206 and/or vehicle system 200.

FIG. 5 illustrates operating temperatures 500, 502, 504, 506, 508, 510of traction motors 314 according to one example of operation of thepropulsion system 300 shown in FIG. 3. The operating temperatures 500,502, 504, 506, 508, 510 are shown alongside a horizontal axis 512representative of time and a vertical axis 514 representative oftemperatures. During a first time period 516, all six of the tractionmotor blowers 316 shown in FIG. 3 are active to work to coolcorresponding ones of the traction motors 314. At a deactivation time518, one of the traction motor blowers 316 is turned off and theremaining traction motor blowers 316 are operated at a reduced speed(e.g., at half of a previous operating speed or at half of the ratedmaximum speed of the traction motor blowers 316).

Subsequent to the deactivation time 518, the operating temperatures 502,504, 506, 508, 510 of the traction motors 314 that are cooled by thetraction motor blower 316 that is on (but operating at reduced speeds)gradually increase over time. The operating temperatures 502, 504, 506,508, 510 may increase because a reduced airflow is generated by thetraction motor blowers 316 to cool the traction motors 314 that arestill on. The operating temperatures 500 of the traction motor 314 thatis deactivated may decrease following the deactivation time 518 becausethe traction motor 314 is no longer active.

The control system 302 can monitor the operating temperatures 500, 502,504, 506, 508, 510 and at least partially base the decision of whetherto turn off one or more traction motors 314 and/or which traction motors314 are to be turned off on the operating temperatures 500, 502, 504,506, 508, 510. For example, at a later decision time 520, the controlsystem 302 may examine determine that one traction motor 314 can beturned off and can examine the operating temperatures 500, 502, 504,506, 508, 510 to determine which traction motor 314 to turn off. Thecontrol system 302 may select one or more of the traction motors 314corresponding to the operating temperatures 502, 504, and/or 506 forturning off because these traction motors 314 exhibit the largestoperating temperatures 502, 504, 506. The control system 302 may turnoff one or more of these traction motors 314 and turn on the deactivatedtraction motor 314. For example, if only a single traction motor 314 isto be turned off to still provide the tractive load demanded by thevehicle system 200, then the control system 302 may decide to turn offthe two traction motors 314 having the operating temperatures 502, 504and to turn on the traction motor 314 having the reduced operatingtemperature 500.

In one embodiment, a method (e.g., for operating a vehicle tractioncontrol system of a vehicle system during movement of the vehiclesystem) includes, during movement of a vehicle system along a route,determining a tractive load demanded by the vehicle system to propel thevehicle system along the route. The vehicle system includes apropulsion-generating vehicle having plural individually controllabletraction motors. The method also can include identifying a firstselected set of the traction motors for deactivation during the movementof the vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and deactivating thetraction motors in the first selected set while at least one of thetraction motors in a first remaining set of the traction motorscontinues to generate tractive effort to propel the vehicle system. Oneor more of the operations of the method (e.g., the determining of atractive load demanded by the vehicle system, identifying the firstselected set of the traction motors, and/or deactivating the tractionmotors) may be performed by one or more processors disposed onboard thevehicle system.

In one aspect, the tractive load demanded by the vehicle system isdetermined independent of a location of the vehicle system.

In one aspect, deactivating the traction motors in the first selectedset occurs at a first time during movement of the vehicle system alongthe route. The method also can include re-determining the tractive loaddemanded by the vehicle system during movement of the vehicle system,re-identifying a different, second selected set of the traction motorsfor deactivation during movement of the vehicle system, and deactivatingthe traction motors in the second selected set at a later, second timewhile at least one of the traction motors in a different, secondremaining set of the traction motors continues to generate the tractiveeffort to propel the vehicle system.

In one aspect, the traction motors are operably coupled with differentaxles of the propulsion-generating vehicle such that deactivating thetraction motors in the first selected set causes the axles to which thetraction motors in the first selected set are operably coupled to nolonger be rotated by the traction motors.

In one aspect, one or more of determining the tractive load oridentifying the first selected set is performed onboard the vehiclesystem.

In one aspect, the method also can include increasing the tractiveeffort generated by the at least one of the traction motors in the firstremaining set.

In one aspect, increasing the tractive effort can include increasing anoperating state of the at least one of the traction motors in the firstremaining set to a rated capacity of the at least one of the tractionmotors.

In one aspect, identifying the first selected set of the traction motorsfor deactivation includes monitoring operating temperatures of thetraction motors.

In one aspect, the method also includes decreasing an operating speed ofone or more traction motor blowers to reduce airflow produced by the oneor more traction motor blowers to cool the traction motors in the firstremaining set.

In one aspect, deactivating the traction motors in the first selectedset occurs at a first time during movement of the vehicle system alongthe route. The method also can include switching, at a later, secondtime, which of the traction motors are included in the first selectedset for deactivation and which of the traction motors are included inthe first remaining set based at least in part on operating temperaturesof the traction motors.

In another embodiment, a system (e.g., a traction control system)includes one or more processors configured to be disposed onboard avehicle system and to determine, during movement of the vehicle systemalong a route, a tractive load demanded by the vehicle system to propelthe vehicle system. The vehicle system includes a propulsion-generatingvehicle having plural individually controllable traction motors. The oneor more processors also are configured to identify a first selected setof the traction motors for deactivation during movement of the vehiclesystem along the route based at least in part on the tractive loaddemanded by the vehicle system and to deactivate the traction motors inthe first selected set while at least one of the traction motors in afirst remaining set of the traction motors continues to generatetractive effort to propel the vehicle system.

In one aspect, the one or more processors are configured to determinethe tractive load demanded by the vehicle system independent of alocation of the vehicle system.

In one aspect, the one or more processors are configured to deactivatethe traction motors in the first selected set at a first time duringmovement of the vehicle system along the route. The one or moreprocessors can be configured to re-determine the tractive load demandedby the vehicle system during movement of the vehicle system, re-identifya different, second selected set of the traction motors for deactivationduring movement of the vehicle system, and to deactivate the tractionmotors in the second selected set at a later, second time while at leastone of the traction motors in a different, second remaining set of thetraction motors continues to generate the tractive effort to propel thevehicle system.

In one aspect, the traction motors are operably coupled with differentaxles of the propulsion-generating vehicle. The one or more processorscan be configured to deactivate the traction motors in the firstselected set to cause the axles to which the traction motors in thefirst selected set are operably coupled to no longer be rotated by thetraction motors.

In one aspect, the one or more processors are configured to one or moreof determine the tractive load or identify the first selected set whilethe one or more processors are disposed onboard the vehicle system.

In one aspect, the one or more processors are configured to increase thetractive effort generated by the at least one of the traction motors inthe first remaining set.

In one aspect, the one or more processors are configured to increase thetractive effort by increasing an operating state of the at least one ofthe traction motors in the first remaining set to a rated capacity ofthe at least one of the traction motors.

In another embodiment, another system (e.g., another traction controlsystem) includes one or more processors configured to monitor tractiveloads demanded to propel a vehicle system along a route as the vehiclesystem moves along the route. The one or more processors are configuredto identify one or more traction motors of a vehicle in the vehiclesystem to turn off based at least in part in a change in the tractiveloads demanded to propel the vehicle system. The one or more processorsare configured to generate control signals to turn off the one or moretraction motors while one or more other traction motors remain on togenerate tractive forces that meet or exceed the tractive loads demandedto propel the vehicle system during movement of the vehicle system alongthe route.

In one aspect, the one or more processors also are configured toidentify which ones of the one or more traction motors to turn off basedat least in part on operating temperatures of the one or more tractionmotors.

In one aspect, the one or more processors also are configured to reducean operating speed of one or more traction motor blowers that cool theone or more other traction motors that remain on responsive to turningoff the one or more traction motors.

In another embodiment, another method (e.g., for controlling a tractioncontrol system) includes, during movement of a vehicle system along aroute, determining a tractive load demanded by the vehicle system topropel the vehicle system along the route. The vehicle system includes afirst propulsion-generating vehicle having a first plurality ofindividually controllable traction motors and a secondpropulsion-generating vehicle having a second plurality of individuallycontrollable traction motors. The first and second vehicles are linkedto travel together along the route. The method also includes identifyinga first selected set of the first plurality of traction motors fordeactivation during movement of the vehicle system along the route basedat least in part on the tractive load demanded by the vehicle system,deactivating the traction motors in the first selected set while atleast one of the traction motors in a first remaining set of the firstplurality of traction motors continues to generate tractive effort topropel the vehicle system, identifying a second selected set of thesecond plurality of traction motors for deactivation during movement ofthe vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and deactivating thetraction motors in the second selected set while at least one of thetraction motors in a second remaining set of the second plurality oftraction motors continues to generate tractive effort to propel thevehicle system.

In one aspect, the method also can include identifying a third selectedset of one or more of the traction motors in the first plurality oftraction motors of the first propulsion-generating vehicle and one ormore of the traction motors in the second plurality of traction motorsof the second propulsion-generating vehicle, and deactivating thetraction motors in the third selected set while at least one of thetraction motors in the first propulsion-generating vehicle and at leastone of the traction motors in the second propulsion-generating vehiclecontinue to generate the tractive effort to propel the vehicle system.

In another embodiment, another system (e.g., another traction controlsystem) includes one or more processors configured to be disposedonboard a vehicle system and to determine, during movement of thevehicle system along a route, determine a tractive load demanded by thevehicle system to propel the vehicle system along the route. The vehiclesystem includes a first propulsion-generating vehicle having a firstplurality of individually controllable traction motors and a secondpropulsion-generating vehicle having a second plurality of individuallycontrollable traction motors, the first and second vehicles being linkedto travel together along the route. The one or more processors also areconfigured to identify a first selected set of the first plurality oftraction motors for deactivation during movement of the vehicle systemalong the route based at least in part on the tractive load demanded bythe vehicle system, and to deactivate the traction motors in the firstselected set while at least one of the traction motors in a firstremaining set of the first plurality of traction motors continues togenerate tractive effort to propel the vehicle system. The one or moreprocessors also are configured to identify a second selected set of thesecond plurality of traction motors for deactivation during movement ofthe vehicle system along the route based at least in part on thetractive load demanded by the vehicle system, and to deactivate thetraction motors in the second selected set while at least one of thetraction motors in a second remaining set of the second plurality oftraction motors continues to generate tractive effort to propel thevehicle system.

In one aspect, the one or more processors are configured to identify athird selected set of one or more of the traction motors in the firstplurality of traction motors of the first propulsion-generating vehicleand one or more of the traction motors in the second plurality oftraction motors of the second propulsion-generating vehicle, and todeactivate the traction motors in the third selected set while at leastone of the traction motors in the first propulsion-generating vehicleand at least one of the traction motors in the secondpropulsion-generating vehicle continue to generate the tractive effortto propel the vehicle system.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventivesubject matter without departing from its scope. While the dimensionsand types of materials described herein are intended to define theparameters of the inventive subject matter, they are by no meanslimiting and are exemplary embodiments. Many other embodiments will beapparent to one of ordinary skill in the art upon reviewing the abovedescription. The scope of the inventive subject matter should,therefore, be determined with reference to the appended clauses, alongwith the full scope of equivalents to which such clauses are entitled.In the appended clauses, the terms “including” and “in which” are usedas the plain-English equivalents of the respective terms “comprising”and “wherein.” Moreover, in the following clauses, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects. Further, thelimitations of the following clauses are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such clause limitationsexpressly use the phrase “means for” followed by a statement of functionvoid of further structure.

This written description uses examples to disclose several embodimentsof the inventive subject matter and also to enable a person of ordinaryskill in the art to practice the embodiments of the inventive subjectmatter, including making and using any devices or systems and performingany incorporated methods. The patentable scope of the inventive subjectmatter may include other examples that occur to those of ordinary skillin the art. Such other examples are intended to be within the scope ofthe clauses if they have structural elements that do not differ from theliteral language of the clauses, or if they include equivalentstructural elements with insubstantial differences from the literallanguages of the clauses.

The foregoing description of certain embodiments of the inventivesubject matter will be better understood when read in conjunction withthe appended drawings. To the extent that the figures illustratediagrams of the functional blocks of various embodiments, the functionalblocks are not necessarily indicative of the division between hardwarecircuitry. Thus, for example, one or more of the functional blocks (forexample, processors or memories) may be implemented in a single piece ofhardware (for example, a general purpose signal processor,microcontroller, random access memory, hard disk, and the like).Similarly, the programs may be stand-alone programs, may be incorporatedas subroutines in an operating system, may be functions in an installedsoftware package, and the like. The various embodiments are not limitedto the arrangements and instrumentality shown in the drawings.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “an embodiment” or “one embodiment” of theinventive subject matter are not intended to be interpreted as excludingthe existence of additional embodiments that also incorporate therecited features. Moreover, unless explicitly stated to the contrary,embodiments “comprising,” “including,” or “having” an element or aplurality of elements having a particular property may includeadditional such elements not having that property.

Since certain changes may be made in the above-described systems andmethods without departing from the spirit and scope of the inventivesubject matter herein involved, it is intended that all of the subjectmatter of the above description or shown in the accompanying drawingsshall be interpreted merely as examples illustrating the inventiveconcept herein and shall not be construed as limiting the inventivesubject matter.

The invention claimed is:
 1. A method comprising: determining a tractiveload demanded by a vehicle to propel the vehicle along one or moreroutes, the vehicle including plural individually controllable tractionmotors; identifying a first selected set of the traction motors fordeactivation during the movement of the vehicle along the one or moreroutes based at least in part on the tractive load demanded by thevehicle; and deactivating the traction motors in the first selected setwhile at least one of the traction motors in a first remaining set ofthe traction motors continues to generate tractive effort to propel thevehicle, wherein at least one of the traction motors in the firstselected set is coupled with a first wheel or a first axle of thevehicle to rotate the first wheel or the first axle and at least one ofthe traction motors in the first remaining set is coupled with a secondwheel or a second axle of the vehicle to rotate the second wheel or thesecond axle.
 2. The method of claim 1, wherein the tractive loaddemanded by the vehicle is determined based on a difference between adesignated speed of the vehicle and a current speed of the vehicle. 3.The method of claim 1, wherein deactivating the traction motors in thefirst selected set occurs at a first time during movement of the vehiclealong the one or more routes, and further comprising: subsequentlydetermining the tractive load demanded by the vehicle during movement ofthe vehicle, identifying a different, second selected set of thetraction motors for deactivation during movement of the vehicle; anddeactivating the traction motors in the second selected set at a later,second time while at least one of the traction motors in a different,second remaining set of the traction motors continues to generate thetractive effort to propel the vehicle.
 4. The method of claim 1, whereindeactivating the traction motors in the first selected set causes thefirst wheel or the first axle to no longer be rotated by the at leastone traction motor in the first selected set.
 5. The method of claim 1,wherein one or more of determining the tractive load or identifying thefirst selected set is performed onboard the vehicle.
 6. The method ofclaim 1, further comprising increasing the tractive effort generated bythe at least one of the traction motors in the first remaining set. 7.The method of claim 6, wherein increasing the tractive effort includesincreasing an operating state of the at least one of the traction motorsin the first remaining set to a rated capacity of the at least one ofthe traction motors.
 8. The method of claim 1, wherein identifying thefirst selected set of the traction motors for deactivation includesmonitoring operating temperatures of the traction motors.
 9. The methodof claim 1, wherein one or more of the plural traction motors includesone or more traction motor blowers, and further comprising decreasing anoperating speed of the one or more traction motor blowers to reduceairflow produced by the one or more traction motor blowers to cool thetraction motors in the first remaining set.
 10. The method of claim 9,wherein deactivating the traction motors in the first selected setoccurs at a first time during movement of the vehicle along the one ormore routes, and further comprising: switching, at a later, second time,which of the traction motors are included in the first selected set fordeactivation and which of the traction motors are included in the firstremaining set based at least in part on an operating temperature of thetraction motors.
 11. A system comprising: one or more processorsconfigured to determine a tractive load demanded by a vehicle to propelthe vehicle along one or more routes, the vehicle including pluralindividually controllable traction motors, wherein the one or moreprocessors are configured to identify a first selected set of thetraction motors for deactivation during the movement of the vehiclealong the one or more routes based at least in part on the tractive loaddemanded by the vehicle, the one or more processors also configured todeactivate the traction motors in the first selected set while at leastone of the traction motors in a first remaining set of the tractionmotors continues to generate tractive effort to propel the vehicle,wherein at least one of the traction motors in the first selected set iscoupled with a first wheel or a first axle of the vehicle to rotate thefirst wheel or the first axle and at least one of the traction motors inthe first remaining set is coupled with a second wheel or a second axleof the vehicle to rotate the second wheel or the second axle.
 12. Thesystem of claim 11, wherein the one or more processors are configured todetermine the tractive load demanded by the vehicle based on adifference between a designated speed of the vehicle and a current speedof the vehicle.
 13. The system of claim 11, wherein the one or moreprocessors are configured to deactivate the traction motors in the firstselected set at a first time during movement of the vehicle along theone or more routes, wherein the one or more processors are configured tosubsequently determine the tractive load demanded by the vehicle duringmovement of the vehicle, to identify a different, second selected set ofthe traction motors for deactivation during movement of the vehicle, andto deactivate the traction motors in the second selected set at a later,second time while at least one of the traction motors in a different,second remaining set of the traction motors continues to generate thetractive effort to propel the vehicle.
 14. The system of claim 11,wherein the one or more processors are configured to deactivate thetraction motors in the first selected set to stop rotating the firstwheel or the first axle with the at least one traction motor in thefirst selected set.
 15. The system of claim 11, wherein the one or moreprocessors are configured to one or more of determine the tractive loador identify the first selected set from onboard the vehicle.
 16. Thesystem of claim 11, wherein the one or more processors are configured toincrease the tractive effort generated by the at least one of thetraction motors in the first remaining set.
 17. A system comprising: oneor more processors configured to monitor tractive loads demanded topropel a vehicle along one or more routes as the vehicle moves along theone or more routes, the one or more processors configured to identifyone or more traction motors of the vehicle to turn off based at least inpart in a change in the tractive loads demanded to propel the vehicle,wherein the one or more processors are configured to generate controlsignals to turn off the one or more traction motors while one or moreother traction motors remain on to generate tractive forces that meet orexceed the tractive loads that are demanded to propel the vehicle duringmovement of the vehicle along the one or more routes, wherein the one ormore traction motors that are turned off are connected to one or moredifferent wheels or different axles of the vehicle than the one or moretraction motors that remain on.
 18. The system of claim 17, wherein theone or more processors also are configured to identify which ones of theone or more traction motors to turn off based at least in part onoperating temperatures of the one or more traction motors.
 19. Thesystem of claim 17, wherein one or more of the one or more tractionmotors includes one or more traction motor blowers, wherein the one ormore processors also are configured to reduce an operating speed of theone or more traction motor blowers that cool the one or more othertraction motors that remain on responsive to turning off the one or moretraction motors.
 20. The system of claim 17, wherein the one or moreprocessors are configured to identify the one or more traction motors ofthe vehicle to turn off based at least in part in the change in thetractive loads demanded to propel the vehicle and based at least in parton a rated capacity of at least one of the traction motors of thevehicle.
 21. The system of claim 17, wherein the vehicle is anautomobile.